...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Environmental Science & Technology >Pesticide sorption and desorption by lignin described by an intraparticle diffusion model
【24h】

Pesticide sorption and desorption by lignin described by an intraparticle diffusion model

机译：颗粒内扩散模型描述木质素对农药的吸附和解吸

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Lignin was used as a model compound for soil organic matter to gain insight into the mechanisms that control the kinetics of pesticide sorption and desorption. Hydrolytic lignin was immobilized in a matrix of alginate gel, and sorption-desorption experiments were undertaken with isoproturon. Sorption increased with time and was close to equilibrium after 14 days. Desorption was measured after sorption for different time intervals and for a number of successive desorption steps of different lengths. The results showed strong differences between the sorption and desorption isotherms. The ratio of sorbed to dissolved pesticide approached and even exceeded the equilibrium ratio, depending on the number of desorption steps and the length of each equilibration period. A numerical diffusion model was developed to describe radial diffusion into the lignin particles in combination with Freundlich sorption inside the particles. Key model parameters were adjusted to fit the sorption data, and the same parameters were then used to predict stepwise desorption. Desorption was well described by the model, which suggests that sorption and desorption were driven by the same mechanism and occurred at the same rate. The observed difference between the sorption and desorption isotherms could be fully explained by the nonattainment of equilibrium due to slow diffusion into and out of the lignin particles.
机译：木质素被用作土壤有机质的模型化合物，以深入了解控制农药吸附和解吸动力学的机理。将水解木质素固定在藻酸盐凝胶基质中，并用异丙隆进行吸附-解吸实验。吸附随时间增加，并在14天后接近平衡。在不同时间间隔和多个不同长度的连续解吸步骤中，在吸附后测量解吸。结果表明，吸附等温线和解吸等温线之间存在很大差异。取决于解吸步骤的数量和每个平衡期的长度，吸附农药与溶解农药的比例接近甚至超过平衡比例。建立了数值扩散模型，以描述径向扩散到木质素颗粒中并结合颗粒内部的Freundlich吸附。调整关键模型参数以适合吸附数据，然后将相同参数用于预测逐步解吸。该模型很好地描述了解吸，这表明吸附和解吸是由相同的机理驱动的，并且以相同的速率发生。吸附和解吸等温线之间观察到的差异可以完全归因于由于缓慢扩散进出木质素颗粒而无法达到平衡。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号